Natural Polymer-Based Mechanically Strong Hydrogel with Fast Self-Healing for Heavy Metal Ions Removal and...

Area of Science:

• Materials Science
• Polymer Chemistry
• Environmental Engineering
• Electrochemistry

Background:

• Hydrogels are of significant interest for multifunctional applications due to their unique properties.
• Achieving both rapid self-healing and superior mechanical strength in hydrogels simultaneously presents a considerable challenge.
• Existing self-healing hydrogels often compromise on mechanical robustness or healing speed.

Purpose of the Study:

• To fabricate a dual cross-linked hydrogel with enhanced self-healing capabilities and mechanical strength.
• To investigate the hydrogel's potential for heavy metal removal from wastewater.
• To evaluate the hydrogel's performance as a solid-state electrolyte and separator in flexible supercapacitors.

Main Methods:

• Fabrication of a dual cross-linked hydrogel (PAA-Alg-B) using free radical polymerization of acrylic acid and alginic acid.
• Utilized N,N'-methylenebisacrylamide or vinyl-modified nanocellulose as the primary cross-linker and borax as a dynamic cross-linker.
• Assessed self-healing efficiency, mechanical properties (toughness, elongation at break), swelling capacity, heavy metal adsorption kinetics, and electrochemical performance.

Main Results:

• The borax-based hydrogel (PAA-Alg-B) demonstrated rapid self-healing via reversible borate ester bonds and hydrogen bonding.
• Exhibited tunable mechanical strength (toughness: 137 kJ/m³, elongation at break: 1117%) and high swelling capacity (448 g/g).
• Achieved high heavy metal removal efficiencies (Cr³⁺: 87.57 mg/g, Ni²⁺: 114.02 mg/g, Cu²⁺: 99.42 mg/g) and enhanced ionic conductivity when used as a supercapacitor electrolyte after H₂SO₄ treatment.

Conclusions:

• The developed PAA-Alg-B hydrogel offers a promising solution for sustainable wastewater treatment due to its efficient heavy metal adsorption.
• The hydrogel's robust mechanical properties, self-healing ability, and performance as an electrolyte highlight its potential in advanced energy storage devices.
• This study underscores the viability of natural polymer-based hydrogels for addressing environmental and energy challenges.